The present invention relates to an illumination technique for illuminating an irradiated plane using a plurality of optical elements, each of which is capable of spatially modulating light, an exposure technique using such an illumination technique, and a method for manufacturing a device with such an exposure technique.
In a lithography process for manufacturing devices (electronic devices and micro-devices), such as semiconductor devices and liquid crystal display devices, an exposure apparatus such as a batch exposure type projection exposure apparatus, like a stepper, or a scanning exposure type projection exposure apparatus, like a scanning stepper, is used to transfer a predetermined pattern onto a wafer (or glass plate etc.). Exposure wavelengths used in such an exposure apparatus have been shortened to increase the resolution. Excimer laser lights, such as a KrF excimer laser (wavelength, 248 nm) and an ArF excimer laser (wavelength, 193 nm) are nowadays being used as exposure light. Further, F2 laser (wavelength, 157 nm) is also being considered for use as exposure light.
To accurately transfer a fine pattern onto a wafer, an illumination optical system of recent exposure apparatuses is required to illuminate a reticle pattern (or mask pattern) with the optimal light intensity distribution (intensity distribution). For example, one promising technique for improving the focal depth and the resolution of a projection optical system is deformed illumination, which forms an annular or multipolar (for example, dipolar or quadrupolar) light intensity distribution on an illumination pupil plane of an illumination optical system. As one such technique, to convert light from a light source to light having an annular or multipolar light intensity distribution on an illumination pupil plane of an illumination optical system, an exposure apparatus includes a spatial light modulator including a two-dimensional array of a plurality of micromirror elements (for example, a digital micromirror device (DMD)). Such an exposure apparatus changes the inclination angle and the inclination direction of each mirror element to form a predetermined light intensity distribution on an illumination pupil plane of the illumination optical system or a plane conjugated with the illumination pupil plane (refer to, for example, Japanese Laid-Open Patent Publication No. 2002-353105).